Plasma immersion ion implantation was used to implant oxygen ions into silicon with applied voltage pulses of −40 kV and 2.5&mgr;s length. Positive ions, O2+and O+, with a continuous energy distribution between 0 and 40 keV were implanted. Between3×104and3×105pulses, corresponding to nominal doses from2×1016to2×1017/cm2,were used. The resulting oxygen depth profiles were measured with elastic recoil detection analysis using 13.4 MeV&agr;particles. Rutherford backscattering was used to determine possible co-implanted contaminants. The obtained depth profiles were simulated using a linear superposition of calculated single-energy profiles. The results obtained for the energy distribution of the incident ions are compared with calculations obtained from a theoretical model, and the agreement is very good. The incident flux is found to be composed of 34(5)&percent; O2+and 66(5)&percent; O+ions with an Fe contamination of ∼0.5&percent;.©1997 American Institute of Physics.